An electronic origin of charge order in infinite-layer nickelates

A charge order (CO) with a wavevector q similar or equal to (1/3, 0, 0) is observed in infinitelayer nickelates. Here we use first-principles calculations to demonstrate a charge-transfer-driven CO mechanism in infinite-layer nickelates, which leads to a characteristicNi(1+)-Ni2+-Ni1+ stripe state. For every threeNi atoms, due to the presence of near-Fermi-level conduction bands, Hubbard interaction on Ni-d orbitals transfers electrons on one Ni atom to conduction bands and leaves electrons on the other two Ni atoms to become more localized. We further derive a low-energy effectivemodel to elucidate that the COstate arises from a delicate competition betweenHubbardinteractiononNi-d orbitals and charge transfer energy between Ni-d orbitals and conduction bands. With physically reasonable parameters, q = (1/3, 0, 0) CO state is more stable than uniform paramagnetic state and usual checkerboard antiferromagnetic state. Our work highlights the multi-band nature of infinite-layer nickelates, which leads to some distinctive correlated properties that are not found in cuprates.